A compact and highly durable brushless motor may be used as a drive source in a power tool, a hammer driver-drill, for example. An example of a suitable brushless motor is disclosed in U.S. Pat. No. 6,819,022 (and family member Japanese Laid-open Patent Publication 2004-007869). This type of brushless motor includes a rotor disposed on the inner side of a stator, and the rotor comprises a rotor core formed from a stack of steel laminations. The motor includes a motor shaft that extends through the center of the rotor core and that is integrated (made integral) with the rotor core, and a plurality of permanent magnets are affixed to the rotor core.